TWI586014B - Organic light-emitting diode including multi-layered hole transporting layer, and flat display device including the organic light-emitting diode - Google Patents

Description

An organic light emitting diode comprising a multilayer hole transport layer and comprising the organic light Planar display device for photodiode Cross-references to related applications

The present application claims the priority benefit of the application filed with the Korean Intellectual Property Office on December 2, 2011. The application number is 10-2011-0128526, the disclosure of which is hereby incorporated by reference in its entirety. reference.

The following description relates to an organic light-emitting diode comprising a multilayer hole transport layer and a flat display device comprising the organic light-emitting diode.

The organic light emitting diode is a self-luminous device and can generate an image of multicolor light. In addition, the organic light-emitting diode has a wide viewing angle, high contrast, short reaction time, and excellent brightness, driving voltage, and reaction speed.

In the conventional organic light-emitting diode, an anode is formed on a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode are sequentially formed on the anode. In this regard, the hole transport layer, the light-emitting layer, and the electron transport layer are organic layers containing an organic compound. When a voltage is applied to the anode and cathode Between the holes injected from the anode passes through the hole transport layer and moves toward the light-emitting layer, and electrons injected from the cathode pass through the electron transport layer and move toward the light-emitting layer. A hole and an electron, which are carriers, are combined in the light-emitting layer to generate excitons, and then the excitons change from the excited state to the ground state, thereby generating light.

The hole transport material used as the hole transport layer generally has an excellent hole injection function or a hole transfer function, thereby forming a device having a low drive voltage. That is, if a hole transporting material having high hole mobility is used as the hole transporting layer, the driving voltage of the formed device can be substantially reduced. However, due to excessive charge injection, the formed device may have low efficiency and short life. To solve these problems, many efforts have been implemented.

One aspect of an embodiment of the present invention is an organic light emitting diode comprising a multilayer hole transport layer of two different hole transporting compounds to enhance the efficiency and lifetime of the formed device.

One aspect of an embodiment of the present invention is a flat display device including an organic light emitting diode.

An aspect of an embodiment of the present invention is an organic light emitting diode comprising a plurality of layers of a hole transport layer having different combinations of hole injection characteristics, electron stability characteristics, and/or charge generation characteristics; and an organic light emitting layer A flat display device for a polar body. Here, the organic light-emitting diode has high stability due to improved charge balance.

According to an embodiment of the present invention, there is provided an organic light emitting diode comprising: a first electrode; a second electrode facing the first electrode; a light emitting layer interposed between the first electrode and the second electrode; a first mixed layer between the light emitting layer and the first electrode, and the first mixed layer comprises a first compound and a second compound; a second mixed layer between the light emitting layer and the first mixed layer, and the second mixing The layer includes a third compound and a fourth compound; a first charge generating layer interposed between the first mixed layer and the first electrode, and the first charge generating layer comprises the first compound, the second compound, and the first charge generating material; a second charge generating layer interposed between the first mixed layer and the second mixed layer, and the second charge generating layer comprises a third compound, a fourth compound and a second charge generating material; and a light emitting layer and a second mixture a buffer layer between layers, wherein the first compound and the third compound are each independently a compound represented by the following Chemical Formula 1, and the second compound and the fourth compound are each independently represented by the following Chemical Formula 2; Material:

Wherein, in Chemical Formula 1, Ar ₁₁ and Ar ₁₂ are each independently a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group; and e and f are each independently an integer of 0 to 5; R ₅₁ To R ₅₈ and R ₆₁ to R ₆₉ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, an amidino group, hydrazine, Hydrazone, carboxyl and its salts, sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ - a C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₅ -C ₆₀ aryl group, a substituted or unsubstituted C ₅ -C ₆₀ aryloxy group, a substituted or unsubstituted C ₅ - An arylthio group of C ₆₀ ; and R59 is a phenyl group, a naphthyl group, an anthyl group, a biphenyl group or a pyridyl group, or at least one hydrogen atom and at least one atom, a halogen atom, or a hydrogen atom. Oxygen, cyano, nitrate , Amino, carbamimidoyl, hydrazine, hydrazone, a carboxyl group and salts thereof, sulfonic acid and salts thereof, phosphate and salts thereof, a substituted or unsubstituted alkyl group of C ₁ -C _20, the warp a substituted or unsubstituted C ₁ -C ₂₀ alkoxy substituted phenyl, naphthyl, anthryl, biphenyl or pyridyl;

Wherein, in Chemical Formula 2, Ar ₁ to Ar ₃ are each independently a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group; and a and b are each independently an integer of 0 to 5; An integer from 1 to 5; R ₁ to R ₅ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine, a hydrazine, a carboxyl group, and Salts, sulfonates and their salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl groups, substituted or unsubstituted C ₂ -C ₆₀ alkenyl groups, Substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, via Substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio, Si(R ₃₁ )(R ₃₂ )(R ₃₃ ), —N(R ₃₄ )(R ₃₅ ) or a nitrogen atom-containing group, and at least one of R ₁ to R ₅ is a nitrogen atom-containing group; d is 0 An integer of up to 5; R ₁₁ to R ₂₃ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, or a cyanogen Base, nitro, amine, formamidine, hydrazine, hydrazine, carboxyl and its salts, sulfonate and its salts, phosphate and its salts, substituted or unsubstituted C ₁ -C ₆₀ Alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy a substituted, unsubstituted C ₃ -C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₅ -C ₆₀ aryl group, a substituted or unsubstituted C ₅ -C ₆₀ aryloxy group a substituted, unsubstituted C ₅ -C ₆₀ arylthio group, -Si(R ₃₆ )(R ₃₇ )(R ₃₈ ) or -N(R ₃₉ )(R ₄₀ ); and R ₃₁ to R _{The 40} series are independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine, a hydrazine, a carboxyl group, a salt thereof, a sulfonate group and a salt thereof, Phosphate and its salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C _3- C ₆₀ cycloalkyl, substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C _5- C ₆₀ arylthio group or substituted or unsubstituted C ₂ -C ₆₀ heteroaryl group, wherein the nitrogen atom-containing group is a 5-membered aromatic ring group containing a nitrogen atom as a ring atom (5- Membered aromatic ring group), comprising a 6-membered aromatic ring group having a nitrogen atom as a ring atom or a nitrogen atom as a ring atom and fused by a 5-membered aromatic group and a 6-membered aromatic group to form 9- Aromatic ring base.

The highest compounding sub-orbital domain (HOMO) energy level of the second compound may be lower than the highest filling sub-orbital energy level of the first compound by 0.1 eV to 0.2 eV, and the lowest unfilled sub-orbital domain of the second compound (LUMO) The energy level may be lower than the lowest unfilled sub-orbital energy level of the first compound by 0.1 eV to 0.2 eV.

The hole mobility of the first compound can be higher than the hole mobility of the second compound.

The mixing weight ratio of the first compound to the second compound may range from 6:4 to 8:2.

The mixing weight ratio of the third compound to the fourth compound may range from 6:4 to 8:2.

The thicknesses of the first mixed layer and the second mixed layer may each independently range from 40 nm to 60 nm.

The total amount of the first charge generating material may range from 1 to 3 parts by weight based on 100 parts by weight of the first charge generating layer.

The total amount of the second charge generating material may range from 1 to 3 parts by weight based on 100 parts by weight of the second charge generating layer.

The thickness of the first charge generation layer and the second charge generation layer may range from 10 nm to 20 nm.

The buffer layer may contain a compound represented by Chemical Formula 1.

The thickness of the buffer layer may range from 0.1 nm to 30 nm.

The first mixed layer and the first charge generating layer are in electrical contact with each other.

The second mixed layer and the second charge generating layer are in electrical contact with each other.

The organic light emitting diode may include at least one of a hole blocking layer, an electron transport layer, an electron injection layer, and a functional layer having an electron transport function and an electron injection function, wherein at least one layer is interposed between the light emitting layer and the second electrode .

According to another embodiment of the present invention, there is provided a flat display device comprising: a transistor including a source, a drain, a gate and an active layer; and the above organic light emitting diode, wherein the organic light emitting diode The first electrode is electrically connected to the source or the drain.

100, 200‧‧‧ Organic Light Emitting Diodes

110,411‧‧‧Substrate

120, 431‧‧‧ first electrode

130‧‧‧ hole injection layer

141, 241‧‧‧ the first charge generation layer

142, 242‧‧‧ first mixed layer

143, 243‧‧‧ second charge generation layer

144, 244‧‧‧ second mixed layer

140‧‧‧ hole transport layer

150, 250‧‧‧ buffer layer

160, 260‧‧‧ luminescent layer

170, 270‧‧‧ electron transport layer

180, 280‧‧‧electron injection layer

190‧‧‧second electrode

412‧‧‧Insulation

413‧‧‧ gate insulation

414‧‧‧Intermediate insulation

415‧‧‧flat layer

421‧‧‧ active layer

422‧‧‧gate electrode

423‧‧‧Source and drain electrodes

424‧‧‧Contact hole

420‧‧‧ drive circuit

430‧‧‧ hole

The above and other features and advantages of the present invention will be apparent from the embodiments, in which: FIG. 1 is a schematic diagram of an organic light emitting diode according to an embodiment of the present invention; An energy level of an organic light emitting diode of an embodiment; Fig. 3 is a graph showing the life characteristics of the organic light-emitting diodes obtained according to Examples 1 to 4 and the organic light-emitting diodes obtained according to Comparative Examples 1 and 2.

Figure 4 is a cross-sectional view showing an embodiment of a flat display device in accordance with the present invention.

The entire list of elements in the previous text of the component list is modified, but the specific components in the list are not modified.

According to an embodiment of the present invention, there is provided an organic light emitting diode comprising: a first electrode; a second electrode facing the first electrode; a light emitting layer interposed between the first electrode and the second electrode; a first mixed layer between the light emitting layer and the first electrode, and the first mixed layer comprises a first compound and a second compound; a second mixed layer between the light emitting layer and the first mixed layer, and the second mixing The layer includes a third compound and a fourth compound; a first charge generating layer interposed between the first mixed layer and the first electrode, and the first charge generating layer comprises the first compound, the second compound, and the first charge generating material; a second charge generating layer interposed between the first mixed layer and the second mixed layer, and the second charge generating layer comprises a third compound, a fourth compound and a second charge generating material; and a light emitting layer and a second mixture a buffer layer between layers, wherein the first compound and the third compound are each independently a compound represented by the following Chemical Formula 1, and the second compound and the fourth compound are each independently represented by the following Chemical Formula 2; Thereof.

Therefore, in one embodiment, the first compound and the third compound are each independently a compound represented by Chemical Formula 1: Chemical Formula 1

Here, in Chemical Formula 1, Ar ₁₁ and Ar ₁₂ may each independently be a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group.

For example, the Ar ₁₁ and Ar ₁₂ systems may each independently be a substituted or unsubstituted phenyl, substituted or unsubstituted pentalenylene group, substituted or unsubstituted. Substituted indenylene group, substituted or unsubstituted naphthylene group, substituted or unsubstituted azulenylene group, substituted or unsubstituted extension ring Heptalenylene group, substituted or unsubstituted indaceneylene group, substituted or unsubstituted acenaphthylene group, substituted or unsubstituted a fluorenylene group, a substituted or unsubstituted phenalenylene group, a substituted or unsubstituted phenanthrenylene group, a substituted or unsubstituted thiol group ( Anthrylene group), substituted or unsubstituted fluoranthenylene group, substituted or unsubstituted triphenylenylene group, substituted or unsubstituted extension Pyrenylene group, replaced Or unsubstituted chrysenylene group, substituted or unsubstituted naphthacenylene group, substituted or unsubstituted picenylene group, substituted or unsubstituted Substituted perylenylene group, substituted or unsubstituted pentaphenylene group or substituted or unsubstituted hexacenylene.

In Chemical Formula 1, e and f are each independently an integer of 0 to 5.

When e and/or f is 0, the carbazole ring and/or the fluoro ring in Chemical Formula 1 may directly bond the nitrogen atom at the center of the chemical structure shown in Chemical Formula 1. For example, e and f may be 0, 1, or 2, respectively, but are not limited thereto. If e is two or more, two or more of Ar ₁₁ may be the same or different from each other. Further, if f is two or more, two or more of Ar ₁₂ may be the same or different from each other.

In Chemical Formula 1, R ₅₁ to R ₅₈ and R ₆₁ to R ₆₉ each independently may be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group or a formazan group (amidino group). ), hydrazine, hydrazone, carboxyl groups and salts thereof, sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl groups, Substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted Or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted Or unsubstituted C ₅ -C ₆₀ arylthio group.

In Chemical Formula 1, R ₅₉ may be at least one of a phenyl group; a naphthyl group; an anthracenyl group; a biphenyl group; or a pyridyl group, or at least one hydrogen atom having at least one atom, a halogen atom, a hydroxyl group, Cyano, nitro, amine, formamidine, hydrazine, hydrazine, carboxyl and their salts, sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₂₀ Alkyl, substituted or unsubstituted C ₁ -C ₂₀ alkoxy substituted phenyl, naphthyl, anthracenyl, biphenyl or pyridyl.

According to an embodiment of the present invention, the first compound and the third compound are each independently represented by the following Chemical Formula 1A: Chemical Formula 1A

Here, in Chemical Formula 1A, R ₅₁ , R ₅₉ , R ₆₁ and R ₆₂ are as described in Chemical Formula 1.

For example, the first compound and the third compound may be the following compounds 301, respectively, but are not limited thereto:

In one embodiment, the second compound and the fourth compound are each independently a compound represented by the following Chemical Formula 2: Chemical Formula 2

Here, in Chemical Formula 2, the Ar ₁ to Ar ₃ groups may each independently be a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group.

For example, the Ar ₁ to Ar ₃ groups may independently be substituted or unsubstituted phenyl, substituted or unsubstituted phenyl, substituted or unsubstituted extended cyclopentadiene. Substituted, substituted or unsubstituted fluorenyl, substituted or unsubstituted anthranyl, substituted or unsubstituted hydrazino, substituted or unsubstituted hexacycloalkenyl Substituted or unsubstituted dicyclopentadienylphenyl, substituted or unsubstituted vinyl naphthalene, substituted or unsubstituted hydrazine, substituted or unsubstituted hydrazine, Substituted or unsubstituted phenanthrenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted propyl [di] enedifluorenyl, substituted or unsubstituted extended triphenyl , substituted or unsubstituted thiol, substituted or unsubstituted thiol, substituted or unsubstituted fused tetraphenyl, substituted or unsubstituted thiol, substituted Or unsubstituted thiol, substituted or unsubstituted pentaphenyl or substituted or unsubstituted hexaphenyl.

In Chemical Formula 2, a and b are each independently an integer of 0 to 5. If a and/or b is 0, the carbazol ring and/or the fluororing in Chemical Formula 2 may directly bond the nitrogen atom at the center of the chemical structure shown in Chemical Formula 2. For example, a and b may be 0, 1, or 2, respectively, but are not limited thereto. If a is two or more, two or more of Ar ₁ may be the same or different from each other. Further, if b is two or more, two or more of Ar ₂ may be the same or different from each other.

In Chemical Formula 2, c is an integer of 1 to 5. Since c is an integer from 1 to 5, Ar ₃ must be present in Chemical Formula 2. For example, c may be 1 or 2, but is not limited thereto. If c is two or more, two or more of Ar ₃ may be the same or different from each other.

In Chemical Formula 2, R ₁ to R ₅ each independently may be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine, a hydrazine, a carboxyl group, and Salts, sulfonates and their salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl groups, substituted or unsubstituted C ₂ -C ₆₀ alkenyl groups, Substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, via Substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio, Si(R ₃₁ )(R ₃₂ )(R ₃₃ ), —N(R ₃₄ )(R ₃₅ ) or a nitrogen atom-containing group, wherein at least one of R ₁ to R ₅ is a nitrogen atom-containing group (R ₃₁ to R _{35 is} indicated below).

For example, R ₁ to R ₅ may independently be independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine group, a hydrazine group, a carboxyl group, and a salt thereof. a class, a sulfonate and a salt thereof, a phosphate and a salt thereof, a substituted or unsubstituted C ₁ -C ₁₀ alkyl group, a substituted or unsubstituted C ₁ -C ₁₀ alkoxy group, A substituted or unsubstituted C ₅ -C ₂₀ aryl group or a nitrogen-containing atom group, and at least one of R ₁ to R ₅ may be a nitrogen-containing atom group.

Here, the nitrogen atom-containing group is a 5-membered aromatic ring group containing a nitrogen atom as a ring atom, a 6-membered aromatic ring group containing a nitrogen atom as a ring atom, or a nitrogen atom as a ring atom and a fusion atom 5-membered aryl and a 6-membered aryl group to form a 9-membered aromatic ring group. For example, the nitrogen atom-containing group can be represented by the following chemical formulas 4A to 4P:

In Chemical Formulas 4A to 4P, Z ₁₂ , Z ₁₃ , Z ₁₄ and Z ₁₅ may be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine group, or a hydrazine group. Carboxylic acid and its salts, sulfonate and its salts, phosphate and its salts, methyl, ethyl, propyl or butyl. For example, in Chemical Formulas 4A to 4P, Z ₁₂ , Z ₁₃ , Z ₁₄ and Z ₁₅ may each be a hydrogen atom. In Chemical Formulas 4A to 4P, p is an integer of 1 to 6. Here, p can be appropriately determined within the range according to the structures of Chemical Formulas 4A to 4P. Or p is two or more, and two or more Z ₁₂ may be the same or different from each other.

In Chemical Formula 2, d may be an integer of 0 to 5. For example, d may be 0, 1, or 2, but is not limited thereto. D can be appropriately determined in accordance with the structure of Ar ₃ within this range. If d is two or more, two or more R _{1 's} may be the same or different from each other.

In Chemical Formula 2, R ₁₁ to R ₂₃ may each independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine group, a hydrazine group, a carboxyl group, and a salt thereof. , sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₁₀ alkenyl, substituted Or unsubstituted C ₁ -C ₆₀ alkoxy group, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl group, substituted or unsubstituted C ₅ -C ₆₀ aryl group, substituted Or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio, -Si(R ₃₆ )(R ₃₇ )(R ₃₈ ) or -N( R ₃₉ ) (R ₄₀ ).

For example, R ₁₂ to R ₁₈ and R ₂₁ to R ₂₃ may each independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine group, or a hydrazine group. , a carboxyl group and a salt thereof, a sulfonate group and a salt thereof, a phosphate group and a salt thereof, and R ₁₁ , R ₁₉ and R ₂₀ each independently represent a hydrogen atom, a methyl group, an ethyl group, a propyl group, a butyl group, Butyl, phenyl, naphthyl, anthracenyl, fluorenyl or fluorenyl, but are not limited thereto.

As for -Si(R ₃₁ )(R ₃₂ )(R ₃₃ ), -N(R ₃₄ )(R ₃₅ ), -Si(R ₃₆ )(R ₃₇ )(R ₃₈ ) and -N(R ₃₉ )(R ₄₀ ), R ₃₁ to R ₄₀ may independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine group, a hydrazine group, a carboxyl group, and a salt thereof. , sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or Unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or Unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio or substituted or Unsubstituted C ₂ -C ₆₀ heteroaryl. For example, R ₃₁ to R ₄₀ may each independently be a hydrogen atom; a halogen atom; a halogen atom; a hydroxyl group; a cyano group; a nitro group; an amine group; a formazan group; a hydrazine; Sulfonates and their salts; phosphates and their salts; C ₁ -C ₁₀ alkyl groups (eg methyl, ethyl, propyl, butyl, pentyl or hexyl); C ₁ -C ₁₀ An alkoxy group (for example, methoxy, ethoxy, propoxy, butoxy or pentyloxy); a C ₁ -C ₁₀ alkyl group; or at least one hydrogen atom having at least one atom, a halogen atom, a C ₁ -C ₁₀ alkane substituted with a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine, a hydrazine, a carboxyl group and a salt thereof, a sulfonate group and a salt thereof, a phosphate group and a salt thereof Oxyl; phenyl; naphthyl; anthracenyl; fluorenyl; fluorenyl; or at least one hydrogen atom having at least one atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, Amine, a hydrazine, a carboxyl group and a salt thereof, a sulfonate group and a salt thereof, a phosphate group and a salt thereof, a C ₁ -C ₁₀ alkyl group, a C ₁ -C ₁₀ alkoxy group substituted phenyl group, a naphthyl group , sulfhydryl, sulfhydryl or sulfhydryl, but not limited to .

In Chemical Formula 2, R ₁ may be a nitrogen atom-containing group, and c and d may each independently be 1 or 2. In some embodiments, in Chemical Formula 2, at least one of R ₂ to R ₅ may be a nitrogen atom-containing group.

According to an embodiment of the present invention, the second compound and the fourth compound may each independently be a compound represented by Chemical Formulas 2A to 2K:

<Chemical Formula 2K>

In Chemical Formulas 2A to 2K, Ar ₁ , Ar ₂ , a and b are as described in Chemical Formula 2, and R _1a , R _1b and R ₃ may each independently be a nitrogen-containing atom group. The nitrogen atom-containing group has been described above.

In Chemical Formulas 2A to 2K, R ₁₁ , R ₁₉ and R ₂₀ may each independently be a substituted or unsubstituted C ₁ -C ₆₀ alkyl group, or a substituted or unsubstituted C ₅ -C ₆₀ aromatic groups.

In Chemical Formulas 2A to 2K, Z ₁ to Z ₄ may independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine group, a hydrazine group, or a carboxyl group. And its salts, sulfonates and their salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl groups, substituted or unsubstituted C ₂ -C ₆₀ alkenyl groups , substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl , substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio -Si(Q ₁ )(Q ₂ )(Q ₃ ) or -N(Q ₄ )(Q ₅ ), and if x or y is 2 or more, the plurality of Z ₁ or Z ₂ systems may be the same or different from each other. Also, x may be an integer from 1 to 8, and y may be an integer from 1 to 3.

Here, Q ₁ to Q ₅ may independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine group, a hydrazine group, a carboxyl group, or a salt thereof. , sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or Unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or Unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio or substituted or Unsubstituted C ₂ -C ₆₀ heteroaryl.

For example, the second compound and the fourth compound may each independently be at least one of the following compounds 2, 8, 14, 15, 16, 20, 31, and 35, but are not limited thereto:

The first compound has a high hole mobility and promotes the transmission of holes due to its high hole mobility. The second compound is a material having a better electron capture function than the first compound.

If the first compound is mixed with a second compound having a lowest unfilled sub-orbital (LUMO) energy level lower than 0.1 eV to 0.2 eV of the first compound, the electron capture function of the first compound can be improved. Therefore, the quenching of the excitons can be reduced, and the formed device can have a long life.

For example, the highest fill-in-orbital domain (HOMO) energy level of the second compound may be lower than the highest fill-in sub-orbital energy level of the first compound from 0.1 eV to 0.2 eV, and the lowest unfilled number of the second compound The orbital energy level may be lower than the lowest unfilled sub-orbital energy level of the first compound by 0.1 eV to 0.2 eV. If the energy levels of the highest filled subtrack domain and the lowest unfilled subtrack domain between the first and second compounds are within these ranges, the electrons may not be substantially captured as the driving voltage increases, and thus the injected charge It can be easily moved, and energy changes can easily occur, and the resulting device can have improved life characteristics.

The amount of the second compound may be between 20 and 40% by weight based on the total amount of the first and second compounds. If the amount of the second compound is within this range, the electron trapping property and the prevention of the driving voltage increase characteristic by the addition of the second compound can reach a satisfactory level.

The hole mobility of the first compound can be higher than the hole mobility of the second compound. That is, the second compound captures electrons to reduce quenching of the excitons, while the first compound provides a high hole mobility.

The first charge generating material and the second charge generating material may each be, for example, a compound having at least one cyano group. The first charge generating material and the second charge generating material may function as a charge generating material, respectively. Non-limiting examples of the first charge generating material and the second charge generating material are benzoquinone derivatives such as tetracyanoquinonedimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyanide- 1,4,5,6-tetrafluoro-tetracyano-1,4-benzoquinonedimethane, F4-CTNQ, but is not limited thereto.

The first charge generating material and the second charge generating material may each independently be at least one of the following compounds 501 and 502:

The term "substituted A" as used herein in the term "substituted or unsubstituted A (wherein A is any substituent)" relates to at least one hydrogen atom in A being bonded to a halogen atom, a halogen atom, or a hydrogen atom. An oxy group, a cyano group, a nitro group, a carboxyl group, a decyl group and a salt thereof, a sulfonate group and a salt thereof, a phosphate group and a salt thereof, a C ₁ -C ₅₀ alkyl group, a C ₂ -C ₅₀ alkenyl group, C ₂ -C ₅₀ alkynyl, C ₁ -C ₅₀ alkoxy, C ₃ -C ₅₀ cycloalkyl, C ₃ -C ₅₀ cycloalkenyl, C ₅ -C ₆₀ aryl, C ₅ -C ₆₀ aryloxy group, C ₅ -C ₆₀ arylthio group, C ₂ -C ₆₀ heteroaryl group, C ₂ -C ₆₀ fused polycyclic group, represented by N(Q ₁₀₁ )(Q ₁₀₂ ) a functional group or a functional group represented by Si(Q ₁₀₃ )(Q ₁₀₄ )(Q ₁₀₅ ), wherein each of Q ₁₀₁ to Q ₁₀₅ may independently be a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, or a cyanogen Base, amino, nitro, nitro, nitrile, carboxyl, decyl, C ₁ -C ₅₀ alkyl, C ₂ -C ₅₀ alkenyl, C ₂ -C ₅₀ alkynyl, C ₁ -C ₅₀ Alkoxy group, C ₃ -C ₅₀ cycloalkyl group, C ₃ -C ₅₀ cycloalkenyl group, C ₅ -C ₆₀ aryl group, C ₅ -C ₆₀ aryloxy group, C ₅ -C ₆ An arylthio group of ₀ , a heteroaryl group of C ₅ -C ₆₀ or a fused polycyclic group of C ₂ -C ₆₀ .

For example, the term "substituted A" relates to at least one hydrogen atom in A being bonded to a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, a nitrile group, a carboxyl group, or a decyl group ( Silyl group), methane, ethane, propane, butane, isobutane, pentane, phenyl, non-phenyl group, cyclopentadienyl, fluorenyl, naphthyl, fluorenyl, And cycloheptatrienyl, dicyclopentadienylphenyl, vinyl naphthyl, anthracenyl, spiro-fluorenyl group, fluorenyl, phenanthryl, fluorenyl, propyl [di] ene , triphenyl, fluorenyl, fluorenyl, fused tetraphenyl, anthracenyl, fluorenyl, pentylphenyl, hexaphenyl, pyrrolyl group, imidazolyl group, benzimidazole Benzoimidazolyl group, phenylbenzoimidazolyl group, pyrazolyl group, pyridinyl group, phenylpyridinyl group, phenylimidazopyridinyl group , pyrazinyl group, pyrimidinyl group, phenylimidazopyrimyl Midinyl group), pyridazinyl group, indolyl group, isoindolyl group, indazolyl group, purinyl group, quinolinyl group , benzoquinolinyl group, phthallazinyl group, naphthyridinyl group, quinoxalinyl group, quinazolinyl group, porphyrin group Cynolinyl group), carazolyl group, phenanthridinyl group, acridinyl group, phenanthrolinyl group, phenazinyl group, puranyl group ), benzopuranyl group, dibenzopuranyl group, heophenyl group, benzo[b]thiophenyl group, dibenzothiophenyl Group), thiazolyl group, isothiazolyl group, benzothiazolyl group, oxazolyl group, isoxazolyl group, benzoxazolyl group Benzooxazolyl group), isoxazole Isozozolyla triazolyl group, phenyltriazolyl group, tetrazolyl group, oxadiazolyl group, phenyloxadiazolyl group, triazinyl (triazinyl group), phenyltriazinyl group, a functional group represented by N(Q ₁₀₁ )(Q ₁₀₂ ) or a functional group represented by Si(Q ₁₀₃ )(Q ₁₀₄ )(Q ₁₀₅ ).

The unsubstituted C ₁ -C ₅₀ alkyl group means a linear or branched saturated hydroxyl group of the alkane, and lacks one of the hydrogen atoms in the alkane. Examples of the C ₁ -C ₅₀ alkyl group having no substituent are a methyl group, an ethyl group, a propyl group, a butyl group, a secondary butyl group, a pentyl group, an isopentyl group, a hexyl group and the like. The substituent in the C ₁ -C ₅₀ alkyl group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The unsubstituted C ₂ -C ₅₀ alkenyl group as used herein refers to a terminal functional group having at least one carbon-carbon in the middle or at the end of the substituted or unsubstituted C ₂ -C ₅₀ alkyl group. Double key. Non-limiting examples of the C ₂ -C ₅₀ alkenyl group having no substituent are vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, propadienyl Group), isoprenyl group and allyl group. The substituent in the C ₂ -C ₅₀ alkenyl group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The C ₂ -C ₅₀ alkynyl group as used herein refers to a terminal functional group having at least one carbon-carbon in the middle or at the end of the substituted or unsubstituted C ₂ -C ₅₀ alkyl group. Three keys. Non-limiting examples of the C ₂ -C ₅₀ alkynyl group having no substituent are an ethynyl group and the like. The substituent in the alkynyl group of the C ₂ -C ₅₀ having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The C ₁ -C ₅₀ alkoxy group used herein without a substituent has the formula represented by -OY, wherein Y is an unsubstituted C ₁ -C ₅₀ alkyl group as defined above. Non-limiting examples of the C ₁ -C ₅₀ alkoxy group having no substituent are methoxy, ethoxy, isopropoxy, butoxy, pentyloxy and the like. The substituent in the C ₁ -C ₅₀ alkoxy group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The C ₃ -C ₅₀ epoxy group which is used herein without a substituent means a cyclic saturated hydroxyl group. Non-limiting examples of the C ₃ -C ₅₀ epoxy group having no substituent are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl and the like. The substituent in the C ₃ -C ₅₀ epoxy group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The C ₃ -C ₅₀ cycloalkenyl group as used herein refers to a cyclic unsaturated hydroxyl group having at least one non-aromatic ring carbon double bond. Non-limiting examples of the C ₃ -C ₅₀ cycloalkenyl group having no substituent are cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, 1,3-cyclohexane Alkenyl, 1,4-cyclohexadienyl, 2,4-cycloheptadienyl, 1,5-cyclooctadienyl, and the like. The substituent in the C ₃ -C ₅₀ cycloalkenyl group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The unsubstituted C ₅ -C ₆₀ aromatic group used herein refers to a monovalent functional group having a cyclic carbon aromatic system having 5 to 60 carbon atoms, and may be a monocyclic functional group or a polycyclic functional group. base. If the unsubstituted C ₅ -C ₆₀ aryl group is a polycyclic functional group, two or more rings may be fused in the unsubstituted C ₅ -C ₆₀ aryl group. Non-limiting examples of the unsubstituted C ₅ -C ₆₀ aryl group are phenyl, cyclopentadienyl, indolyl, naphthyl, anthryl, cycloheptatrienyl, dicyclopentadiene and Phenyl, vinyl naphthyl, anthracenyl, fluorenyl, fluorenyl, phenanthryl, anthracenyl, propyl [di] ene fluorenyl, triphenyl, fluorenyl, fluorenyl, fused tetraphenyl, fluorene Base, fluorenyl, pentaphenyl, hexaphenyl. The substituent in the aromatic group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituted A" as described in detail above.

The unsubstituted C ₅ -C ₆₀ aryloxy group used herein refers to a monovalent functional group in which a carbon atom in the C ₅ -C ₆₀ aromatic group is bonded by an oxygen (-O-). The substituent in the aryloxy group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The unsubstituted arylthio group of C ₅ -C ₆₀ used herein refers to a monovalent functional group in which a carbon atom in the C ₅ -C ₆₀ aromatic group is bonded by a sulfur (-S-). Examples of the unsubstituted C ₅ -C ₆₀ arylthio group are a phenyl thio group, a naphthyl thio group, an indanylthio group, and an indenyl thio group. Group). The substituent in the arylthio group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituted A" as described in detail above.

The heteroaryl group of C ₂ -C ₆₀ as used herein refers to a monovalent functional group having at least one ring having at least one hetero atom selected from the group consisting of nitrogen, oxygen, phosphorus and sulfur, and having 2 to 60 carbon atoms and may be a monocyclic or polycyclic functional group. Without the substituents of C ₂ -C ₆₀ heteroaryl group is a polycyclic functional group, comprising no more than two of the ring of the substituent group of C ₂ -C ₆₀ hetero aryl group may be fused. Examples of the unsubstituted C ₂ -C ₆₀ heteroaryl group are pyrrolyl, imidazolyl, pyrazolyl, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, isodecyl, fluorenyl, fluorenyl Azyl, fluorenyl, quinolyl, benzoquinolyl, pyridazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, porphyrinyl, oxazolyl, phenanthryl, acridinyl, Polinolinyl, cyanozinyl, benzoxazolyl, benzimidazolyl, furanyl group, benzofuranyl group, thienyl, benzothienyl, thiazolyl, isothiazolyl, Benzothiazolyl, isoxazolyl, oxazolyl, triazolyl, tetrazolyl, oxadiazolyl, triazinyl, benzoxazolyl and the like. The substituent in the heteroaryl group of the C ₂ -C ₆₀ having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The unsubstituted C ₂ -C ₆₀ fused polycyclic group as used herein refers to a monovalent functional group comprising two or more fused rings and 2 to 60 carbon atoms. The unsubstituted C ₂ -C ₆₀ fused polycyclic group may be a polycyclic substituent, or the like. The substituent in the C ₂ -C ₆₀ fused polycyclic group having a substituent may be one of the substituents in the term "substituent A" described in detail above.

The C ₁ -C ₅₀ alkylene group as used herein refers to a linear or branched divalent functional group in which two hydrogen atoms are defective. Examples of the alkyl group of the unsubstituted C ₁ -C ₅₀ it may be stretched by reference to the above unsubstituted alkyl group of C ₁ -C _50's may be learned. The substituent in the C ₁ -C ₅₀ alkylene group having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

As used herein, the unsubstituted C ₅ -C ₆₀ extended aryl group means a divalent functional group having a carbocyclic aromatic system having 5 to 60 carbon atoms, and the divalent functional group may be a single ring or more Ring functional group. Unsubstituted C ₅ -C ₆₀ group of examples of the arylene group may be unsubstituted by reference to the above group of C ₅ -C ₆₀ aryl group is understood the. The substituent in the extended aryl group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituted A" as described in detail above.

The unsubstituted aryloxy group of C ₅ -C ₆₀ used herein refers to a divalent functional group in which a carbon atom in a C ₅ -C ₆₀ extended aryl group is bonded via an oxygen (-O-) . The substituent in the extended aryl group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituted A" as described in detail above.

The unsubstituted arylthio group of C ₅ -C ₆₀ as used herein refers to a divalent functional group in which a carbon atom in a C ₅ -C ₆₀ extended aryl group is bonded via a sulfur (-S-) . The substituent in the extended arylthio group of the C ₅ -C ₆₀ having a substituent may be one of the substituents in the term "substituent A" as described in detail above.

The unsubstituted C ₂ -C ₆₀ heteroaryl group as used herein refers to a divalent functional group having at least one ring having at least one hetero atom selected from the group consisting of nitrogen, oxygen, phosphorus and sulfur, and It has 2 to 60 carbon atoms and may be a monocyclic or polycyclic functional group. Without the substituents of C ₂ -C ₆₀ heteroaryl group is a polycyclic functional group, comprising no more than two of the ring of the substituent group of C ₂ -C ₆₀ hetero aryl group may be fused. Examples ₂ -C ₆₀ hetero arylene group of the group of unsubstituted C can see by unsubstituted heteroaryl group of C ₂ -C _60, be learned. The substituent in the heterocyclic aryl group of the C ₂ -C ₆₀ having a substituent may be one of the substituents in the term "substituted A" as described in detail above.

The organic light emitting diode including the multilayer hole transport layer may comprise a structure in the following order: a first charge generating layer, wherein the first and second compounds having different energy levels have charge generation a first charge generating material doped/first mixed layer/second charge generating layer having first and second compounds, wherein the third and fourth compounds having different energy levels and the second charge having charge generating ability A material doped/second mixed layer/buffer layer/light emitting layer having third and fourth compounds is produced.

In this regard, the first compound (or the third compound) and the second compound (or the fourth compound) may independently have a triarylamine structure, a carbazole structure, and a fluorene structure, respectively, and due to the inclusion of the above structures, these compounds It has a high glass transition temperature and/or melting point and is stable to electron injection. Therefore, when the organic light-emitting diode is driven and when the hole-related layer containing the first compound (or the third compound) and the second compound (or the fourth compound) is interposed between the electrode pairs of the organic light-emitting diode, The hole-related layer can exhibit a strong thermal impedance to the Joule heat generated by the organic layer disposed between the electrode pairs. Further, the first compound (or the third compound) and the second compound (or the fourth compound) each have a fluorine ring, respectively, and therefore, the layer containing the compound may have a property of being highly planarized, and the organic light including the layer The diode can have excellent electronic properties. For example, if a mixture comprising the first compound (or the third compound) and the second compound (or the fourth compound) is interposed between the light-emitting layer and the anode, since the electrons move through the light-emitting layer, the organic light-emitting diode Degradation may not occur substantially.

Further, in the second compound (or the fourth compound), at least one of R ₁ to R ₅ is substantially a nitrogen atom-containing group, and due to the nitrogen atom-containing group, the mobility of the hole can be easily control. Therefore, in the organic light-emitting diode containing the second compound (or the fourth compound), since the balance between electrons and holes is increased and maximized due to the nitrogen atom-containing group, the light-emitting efficiency of the light-emitting layer can be increased. Typically, the hole moves at a faster rate than the electron moving speed. Therefore, compared to the electrons passing through the cathode to the light-emitting layer, there are too many holes that pass through the anode to reach the light-emitting layer, and the exciton-forming region in the light-emitting layer cannot be biased to the cathode due to excessive holes, or The organic layer, such as the light-emitting layer, may be degraded, thereby reducing the lifetime of the organic light-emitting diode. However, the second compound (or the fourth compound) having at least one of R ₁ to R ₅ is a nitrogen atom-containing group, and the mobility of the hole can be controlled due to the inclusion of the nitrogen atom-containing group. Therefore, the balance between the holes and the electrons reaching the light-emitting layer can be increased and maximized, and thus the formed organic light-emitting diode can have a long life. Further, since the electrons diffused from the light-emitting layer are stably stabilized in the nitrogen-containing atomic group in the second compound (or the fourth compound), the formed organic light-emitting diode can have a long life.

Further, the nitrogen atom-containing group in the second compound (or the fourth compound) is not directly bonded to the nitrogen at the center of the chemical structure shown in Chemical Formula 2, but is attached to the chemistry shown in Chemical Formula 2 by a fluorine ring or Ar ₃ Nitrogen in the center of the structure. By doing so, the nitrogen-containing atomic group which may be at least one of R ₁ to R ₅ may not be directly bonded to the nitrogen, and changing the hole-related properties, such as the hole mobility characteristics, may be reduced or avoided, and thus improved. The efficiency of the organic light-emitting diode.

Therefore, the first mixed layer (or the second mixed layer) comprises a mixture comprising the second compound (or the fourth compound) and the first compound (or the third compound) having excellent electronic properties and also in the first mixture In the layer (or the second mixed layer), the hole mobility can be controlled and the non-luminescence quenching occurring between the interface close to the light-emitting layer and the adjacent layer to the light-emitting layer due to the second compound (or the fourth compound) can be controlled. The efficiency and life of the formed organic light-emitting diode are increased.

For example, the organic light emitting diode may have the following structure: first electrode / first charge generating layer / first mixed layer / second charge generating layer / second mixed layer / buffer layer / light emitting layer / electron transport Layer/second electrode.

The highest filling sub-orbital energy level of the first compound may be higher than the highest filling sub-orbital energy level of the second compound by 0.1 eV to 0.2 eV, and the lowest unfilled sub-orbital energy level of the first compound may be lower than The lowest unfilled sub-orbital energy level of the second compound is 0.1 eV to 0.2 Ev. If the highest fill subtrack domain and the lowest unfilled subtrack domain between the first compound and the second compound are within these ranges, The sub-capture can be captured without substantially increasing the driving voltage, the injected charge can be easily moved and the energy transition can easily occur, and the device formed can have improved lifetime characteristics.

For example, the highest fill-in sub-orbital energy level and the lowest unfilled sub-orbital energy level of the first compound may be -4.7 to -4.8 eV and -0.9 to -1.0 eV, respectively, and the highest filling of the second compound. The full-sub-orbital energy level and the lowest unfilled sub-orbital energy level can be -4.8 to -4.9 eV and -1.0 to -1.1 eV, respectively.

The hole mobility of the first compound can be higher than the electromotive force of the second compound. Due to the mixing of the first compound having a relatively high hole mobility and the second compound having a relatively low hole mobility, the hole mobility can be controlled and excess charge injection can be reduced or avoided, thus forming the device Can have a longer life.

The mixing weight ratio of the first compound to the second compound may range from 6:4 to 8:2. If the mixing weight ratio of the first compound to the second compound is within this range, the hole mobility can be controlled to increase the efficiency and lifetime of the device formed. The mixing weight ratio of the third compound to the fourth compound may range from 6:4 to 8:2. If the mixing weight ratio of the third compound to the fourth compound is within this range, the hole mobility can be controlled to increase the efficiency and life of the formed device.

The thickness of each of the first mixed layer and the second mixed layer may range from 40 nm to 60 nm. If the thicknesses of the first mixed layer and the second mixed layer are within this range, the hole mobility can be appropriately controlled without substantially increasing the driving voltage.

The total amount of the first charge generating material may range from 1 to 3 parts by weight based on 100 parts by weight of the first charge generating layer. The first charge generating material is a material for generating charges, and may be uniformly distributed or unevenly distributed in the first charge generating layer. However, the distribution of the first charge generating material in the first charge generating layer may not be limited to the above disclosure. If the total amount of the first charge generating material is within this range, the total amount of appropriate charges can be generated in the first charge generating layer.

The total amount of the second charge generating material may range from 1 to 3 parts by weight based on 100 parts by weight of the second charge generating layer. The second charge generating layer may be uniformly distributed or unevenly distributed in the first The second charge is generated in the layer. However, the distribution of the second charge generating material in the second charge generating layer may not be limited to the above disclosure. If the total amount of the second charge generating material is within this range, the total amount of appropriate charges can be generated in the second charge generating layer.

The thickness of each of the first charge generation layer and the second charge generation layer may range from 10 nm to 20 nm. If the thicknesses of the first charge generating layer and the second charge generating layer are within this range, the hole mobility can be appropriately controlled without substantially increasing the driving voltage.

The buffer layer may be disposed between the light emitting layer and the second mixed layer. If the luminescent layer directly contacts the second mixed layer, the second mixed layer can attract electrons, thereby reducing the lifetime of the luminescent layer. Therefore, the buffer layer interposed between the light-emitting layer and the second mixed layer can avoid or reduce the attraction of electrons, resulting in improved life. Moreover, the buffer layer can compensate the optical resonance distance according to the wavelength of the light-emitting layer, thereby improving the efficiency of the formed organic light-emitting diode.

The buffer layer may include a compound represented by Chemical Formula 1 having an excellent hole mobility, but is not limited thereto. For example, as a material for forming a buffer layer, a mixed material containing a first compound and a luminescent host material can be used. In this example, the highest fill sub-track domain energy level of the buffer layer may exist between the highest fill sub-track domain energy level of the second mixed layer and the highest fill sub-track domain energy level of the light-emitting layer, thereby making electricity Holes can be easily transferred.

The thickness of the buffer layer may range from 0.1 nm to 30 nm. If the thickness of the buffer layer is within this range, the efficiency of the formed organic light-emitting diode can be increased since the optical resonance distance is compensated without substantially increasing the driving voltage according to the wavelength of the light-emitting layer.

The first mixed layer may contact the first charge generating layer. If the first mixed layer contacts the first charge generating layer, the balance of charges can be improved.

The second mixed layer may contact the second charge generating layer. If the second mixed layer contacts the second charge generating layer, the balance of charges can be improved.

According to an embodiment of the present invention, the organic light emitting diode may include at least one of a hole blocking layer, an electron transport layer, an electron injection layer, and a functional layer having an electron transport function and an electron injection function, and the at least one layer is Between the light-emitting layer and the second electrode.

For example, the organic light emitting diode may have a structure in which the first electrode/first and second compounds having different energy levels are doped with the first charge generating layer of the first charge generating material/including the first and the first a first mixed layer of two compounds/a second charge generating layer having different energy levels and a second charge generating layer doped with a second charge generating material/a second mixed layer/buffer layer/light emitting comprising third and fourth compounds Layer/electron transport layer/electron injection layer/second electrode.

1 is a schematic view of an organic light emitting diode 100 according to an embodiment of the present invention. Here, referring to FIG. 1, a structure of an organic light emitting diode according to an embodiment of the present invention, and a method of manufacturing an organic light emitting diode according to an embodiment of the present invention will be described in detail.

The organic light emitting diode 100 sequentially includes the substrate 110, the first electrode 120, the hole injection layer 130, the first charge generation layer 141, the first mixed layer 142, the second charge generation layer 143, and the second mixed layer in this order. 144. The buffer layer 150, the light emitting layer 160, the electron transport layer 170, the electron injection layer 180, and the second electrode 190.

The substrate 110 may be one of different suitable substrates for the organic light-emitting diode, and may be a glass substrate or have excellent mechanical strength, thermal stability, penetration, surface smoothness, and easy handling. Waterproof transparent plastic substrate.

The first electrode 120 may be formed by providing a first electrode material to a substrate by deposition or sputtering. If the first electrode 120 is an anode, in order to facilitate the injection of the hole, the first electrode material may be selected from materials having a high work function. Also, the first electrode 120 may be a reflective electrode or a penetrating electrode. The first electrode material may be a transparent and highly conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), or the like. Alternatively, magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), etc. are used as the first The electrode material, the first electrode 120 may be formed as a reflective electrode. The first electrode 120 can comprise two different materials. For example, the first electrode 120 can have a two-layer structure comprising two different materials. However, the structure of the first electrode 120 is not limited thereto.

The hole injection layer 130 is formed on the first electrode 120. However, depending on the purpose, the hole injection layer 130 may not be formed.

The hole injection layer 130 may be formed on the first electrode 120 by a different suitable method, such as vacuum deposition, wet process, laser transfer, etc., as described above.

When the hole injection layer 130 is formed by vacuum deposition, the deposition conditions may vary depending on the material used to form the hole injection layer 130 and the structure and thermal characteristics of the hole injection layer 130. For example, the deposition conditions may include a deposition temperature of about 100 ° C to 500 ° C, a vacuum pressure of about 10 ^-8 to about 10 ^-3 torr, and a deposition rate of about 0.01 Å / sec to about 100 Å / sec. However, the deposition conditions are not limited to this.

When the hole injection layer 130 is formed by a wet method using spin coating, the coating conditions may vary depending on the material used to form the hole injection layer 130, and depending on the structure and thermal characteristics of the hole injection layer 130. For example, the coating speed may range from about 2000 rpm to about 5000 rpm, and the temperature at which the heat treatment may be performed after coating to remove the solvent may range from about 80 °C to about 200 °C. However, the coating conditions are not limited to this.

The material of the hole injection layer may be one of the conventional hole injection materials. Non-limiting examples of materials for the hole injection layer are phthalocyanine compounds such as copper phthalocyanine, m-MTDATA (the structure of which is described below), TDATA (the structure of which is described below), 2-TNATA (the structure of which is described below) ), polyaniline/dodecylbenzenesulfonic acid (Pani/DBSA), poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS), polyaniline/ Camphorsulfonic acid (Pani/CSA), polyaniline/poly(4-styrenesulfonate) (Pani/PSS), and the like.

The hole injection layer 130 may have a thickness of from about 100 angstroms to about 10,000 angstroms, for example, from about 100 angstroms to about 1000 angstroms. When the thickness of the hole injection layer 130 is within this range, the hole injection layer 130 can have satisfactory hole injection characteristics without increasing the driving voltage.

Next, the hole transport layer 140 may be formed on the hole injection layer 130. The hole transport layer 140 may include a first charge generation layer 141, a first mixed layer 142, a second charge generation layer 143, and a second mixed layer 144 sequentially deposited in sequence.

First, the first charge generation layer 141 may be formed on the hole injection layer 130 by vacuum deposition, wet deposition, laser transfer, or the like. When the first charge generation layer 141 is formed by vacuum deposition or spin coating, the conditions of deposition or coating may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may be used to form the first charge generation layer. 141 material changes.

As a material forming the first charge generation layer 141, a mixture of the first compound and the second compound, which is doped with the first charge generating material, can be used. In this regard, the weight ratio of the first compound to the second compound may range from 6:4 to 8:2, and based on 100 parts by weight of the first charge generating layer 141, the total of the first charge generating material The amount may range from 1 to 3 parts by weight.

The thickness of the first charge generation layer 141 may range from 10 nm to 20 nm. If the thickness of the first charge generation layer 141 is within this range, the first charge generation layer 141 may have satisfactory hole transport characteristics and a sufficient charge amount without substantially increasing the drive voltage.

The first mixed layer 142 may be formed on the first charge generation layer 141 by, for example, vacuum deposition, wet processing, or laser transfer. When the first mixed layer 142 is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may depend on the material used to form the first mixed layer 142. And change.

As a material forming the first mixed layer 142, a mixture containing the first compound and the second compound can be used. In this regard, the weight ratio of the first compound to the second compound may range from 6:4 to 8:2.

The thickness of the first mixed layer 142 may range from 40 nm to 60 nm. If the thickness of the first mixed layer 142 is within this range, the first mixed layer 142 may have satisfactory hole transport characteristics and sufficient hole mobility without substantially increasing the driving voltage.

The second charge generation layer 143 can be formed on the first mixed layer 142 by, for example, vacuum deposition, wet processing, or laser transfer. When the second charge generation layer 143 is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may be used to form the second charge generation layer 143. The material changes.

As a material forming the second charge generating layer 143, a mixture of the third compound and the fourth compound, which is doped with the second charge generating material, can be used. In this regard, the weight ratio of the third compound to the fourth compound may range from 6:4 to 8:2, and based on 100 parts by weight of the second charge generating layer, the total amount of the second charge generating material It can be in the range of 1 to 3 parts by weight.

The thickness of the second charge generation layer 143 may range from 10 nm to 20 nm. If the thickness of the second charge generation layer 143 is within this range, the second charge generation layer 143 may have satisfactory hole transport characteristics and a sufficient charge amount without substantially increasing the drive voltage.

The second mixed layer 144 can be formed on the second charge generation layer 143 by, for example, vacuum deposition, wet method, or laser transfer. When the second mixed layer 144 is vacuum deposited or spin coated The formation, deposition or coating conditions can be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating can vary depending on the material used to form the second mixed layer 144.

As a material for forming the second mixed layer 144, the weight ratio of the third compound to the fourth compound may be in the range of 6:4 to 8:2 in this regard.

The thickness of the second mixed layer 144 may range from 40 nm to 60 nm. If the thickness of the second mixed layer 144 is within this range, the second mixed layer 144 may have satisfactory hole transport characteristics and sufficient hole mobility at substantially no increase in driving voltage.

The buffer layer 150 may be formed on the second mixed layer 144 by, for example, vacuum deposition, wet processing, or laser transfer. When the buffer layer 150 is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may vary depending on the material used to form the buffer layer 150.

The material used to form the buffer layer 150 can be the first compound. According to an embodiment of the present invention, a mixture comprising the first compound and the luminescent host material may be used as a material for forming a buffer layer.

The thickness of the buffer layer 150 may range from 0.1 nm to 30 nm. If the thickness of the buffer layer 150 is within this range, the driving voltage may not be excessively increased, and since the optical resonance distance can be compensated according to the wavelength of the light emitted by the light-emitting layer 160, the efficiency of the formed organic light-emitting diode is improved.

The light emitting layer 160 may be formed on the buffer layer 150 by, for example, vacuum deposition, wet processing, or laser transfer. When the light-emitting layer 160 is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may vary depending on the material used to form the light-emitting layer 160.

The luminescent layer 160 can comprise a known phosphorescent host, a fluorescent host, a phosphorescent dopant, or a fluorescent dopant. As a known main body, 4,4'-N,N'-dicarbazole-biphenyl can be used. (4,4'-N,N'-dicarbazole-biphenyl, CBP), 9,10-di-naphthalene-2-yl-anthracene (ADN) The structure is described below, TPBI (the structure of which is described below), TBADN (the structure of which is described below), E3 (the structure of which is described below), but is not limited thereto.

As the red dopant, PtOEP (whose structure is described below), Ir(piq) ₃ (the structure of which is described below), Btp ₂ Ir(acac), or the like can be used, but is not limited thereto.

Also, as the green dopant, Ir(ppy) ₃ (ppy = phenylpyridine, the structure of which is described below), Ir(ppy) ₂ (acac) (the structure of which is described below), Ir(mpyp) ₃ ( The structure is as described below, etc., but is not limited thereto.

As the blue dopant, F ₂ Irpic (the structure of which is described below), (F ₂ ppy) ₂ Ir(tmd) (the structure of which is described below), Ir(dfppz) ₃ (the structure of which is described below), DPVBi (having the structure described below), 4,4'-bis(4-diphenylaminostaryl)biphenyl, DPAVBi, the structure of which is as follows Description), 2,5,8,11-tetra-tert-butyl perylene (TBPe, the structure of which is described below), etc., but is not limited thereto.

If the light-emitting layer 160 comprises a host and a dopant, the total amount of the dopant may be from about 0.01 to about 15 parts by weight based on 100 parts by weight of the host, but is not limited thereto.

The luminescent layer 160 can have a thickness from about 100 angstroms to about 1000 angstroms, for example, from about 200 angstroms to about 600 angstroms. If the thickness of the light-emitting layer 160 is within this range, excellent light-emitting characteristics can be obtained without substantially increasing the driving voltage.

If the luminescent layer 160 comprises a phosphorescent host, in order to avoid diffusion of triple excitons or holes into the electron transporting layer 170, the hole blocking layer HBL (not shown in FIG. 1) may be deposited by vacuum deposition, wet method or laser transfer. It is formed between the electron transport layer 170 and the light emitting layer 160. If the hole barrier layer is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the deposition or coating conditions may vary depending on the material used to form the hole barrier layer. . As the material of the hole blocking layer, one of the known hole blocking layer materials can be used, and examples thereof are an oxadiazole derivative, a triazole derivative, a phenanthroline derivative and the like.

The thickness of the hole barrier layer can range from about 50 angstroms to about 1000 angstroms, for example, from about 100 angstroms to about 300 angstroms. If the thickness of the hole blocking layer is within the above range, excellent hole blocking characteristics can be obtained without substantially increasing the driving voltage.

Next, the electron transport layer 170 can be formed by various methods such as vacuum deposition, wet method, or laser transfer as described above. The electron transport layer may comprise a known electron transport material. Non-limiting examples of known electron transport materials for the quinoline derivative, such as tris (8-quinolinolato) aluminum (tris (8-quinolinolate) aluminum , Alq 3), TAZ ( the structure in the following description), BAlq (which The structure is described below) and beryllium bis (benzoquinolin-10-olate, Bebq ₂ ).

Electron transport layer 170 can comprise an electron transporting organic compound. Non-limiting examples of electron transporting organic compounds are 9,10-di-naphthalene-2-yl-anthracene (ADN) and oxime-based compounds, such as the following compounds 601 And 602:

The electron transport layer 170 can have a thickness from about 100 angstroms to about 1000 angstroms, for example, from about 150 angstroms to about 500 angstroms. If the thickness of the electron transport layer 170 is within the above range, excellent electron transport characteristics can be obtained without substantially increasing the driving voltage. If the electron transport layer 170 is formed by vacuum deposition or spin coating, the deposition or coating conditions may be similar to the application to form the hole injection layer 130, although the conditions of deposition or coating may vary depending on the material used to form the electron transport layer 170. .

The electron injection layer 180 can be deposited on the electron transport layer 170 by using a material that allows electrons to be easily injected from the anode. As a material for forming the electron injecting layer 180, for example, lithium fluoride, sodium chloride, cesium fluoride, lithium oxide, cerium oxide or lithium quinolate may be used for any known electron injecting material. Alternatively, a heterocyclic compound of Chemical Formula 1 can also be used. Deposition or coating conditions of the electron injection layer 180 The hole injection layer 130 may be formed similarly to the application, although the conditions of deposition or coating may vary depending on the material used to form the electron injection layer 180.

The thickness of the electron injecting layer 180 can range from about 1 angstrom to about 100 angstroms, for example, from about 3 angstroms to about 90 angstroms. If the thickness of the electron injecting layer 180 is within the above range, excellent electron injecting characteristics can be obtained without substantially increasing the driving voltage.

The second electrode 190 is formed on the electron injection layer 180 as a reflective electrode. The second electrode 190 can serve as a cathode for the electron injecting electrode, and in this example, a low work function metal, an alloy, a conductive compound, and a mixture thereof can be used as the second electrode material. In more detail, lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg) can be formed. -Ag) as a film used as a reflective electrode. Also, if an organic light emitting diode is used for the top light emitting diode device, ITO or IZO may be used to form a transparent electrode.

In the above, the organic light-emitting diode can be described with reference to FIG. However, the structure of the organic light emitting diode is not limited to the structure shown in FIG.

Fig. 2 shows the energy levels of the organic light emitting diode 200 according to an embodiment of the present invention.

The organic light emitting diode may include a first charge generation layer 241, a first mixed layer 242, a second charge generation layer 243, a second mixed layer 244, a buffer layer 250, a light emitting layer 260, an electron transport layer 270, and an electron injection layer 280. . Because the first charge generation layer 241 includes the first compound, the second compound, and the first charge generation material, and the second charge generation layer 243 includes the third compound, the fourth compound, and the second charge generation material, the first and second charges The generation layers 241 and 243 may have similar highest fill sub-track domain energy levels and lowest unfilled sub-track domain energy levels. The first and second charge generating layers 241 and 243 respectively include a first charge generating material and a second charge generating material, and the highest filled sub-track domain energy level and the lowest unfilled sub-track domain energy level are represented by dotted lines. The highest fill sub-track domain level and the lowest unfilled sub-track domain energy level of each of the first and second charge generating materials are relatively low; the first and second charge generating materials can provide a reduction of the first charge generating layer The driving voltage of 241 and the second charge generating layer 243.

The first mixed layer 242 comprises a first compound and a second compound, and the second mixed layer 244 comprises a third compound and a fourth compound, and the first and second mixed layers 242 and 244 have similar highest filling sub-track energy The order and the lowest unfilled sub-track domain energy level.

The planar display device including the transistor may include an organic light emitting diode. Therefore, another aspect of the present invention provides a flat display device comprising: a transistor including a source, a drain, a gate, and an active layer; and an organic light emitting diode (including a multilayered hole transport layer), wherein the organic light emitting The first electrode of the diode is electrically connected to the source or the drain.

According to an embodiment of the present invention, as shown in FIG. 4, the flat display device includes a driving circuit 420 electrically connected to a pixel unit on the substrate 411. An insulating layer 412, such as a carrier layer and/or a buffer layer, can be formed on the substrate 411 to planarize the surface of the substrate and substantially prevent the diffusion of impurities and external contaminants and air. A transistor as the driving circuit 420 is formed on the insulating layer 412. According to some embodiments, a top gate thin film transistor can be used. However, it will be understood that a variety of other forms of transistors can be used. The active layer 421 of the transistor comprises a semiconductor material and is disposed on the insulating layer 412. The gate insulating layer 413 covers the active layer 421. The active layer 421 may comprise an inorganic semiconductor material (eg, amorphous germanium or polysilicon) or an organic semiconductor material, and may have a source region, a drain region, and a channel region between the source region and the drain region. The gate electrode 422 is disposed on the gate insulating layer 413, and the intermediate insulating layer 414 covers the gate electrode 422. The source and drain electrodes 423 are disposed on the intermediate insulating layer 414 and contact the active layer through the contact holes 424. The flat layer 415 covers the source and drain electrodes 423. It will be understood that the stacked structure of the transistors is not limited to this structure, and the transistor may have any suitable structure. The first electrode 431 of the organic light emitting diode is formed on the flat layer 415, and the source and the drain electrode 423 are electrically connected by the hole 430. A pixel defining layer (not shown) is a thin inorganic layer formed on the first electrode 431. An opening is formed on the pixel defining layer to expose the first electrode 431 through the opening.

The active layer of the transistor may be, for example, an amorphous germanium layer, a crystalline germanium layer, an organic semiconductor layer, a semiconductor oxide layer, or the like.

Here, an organic light-emitting diode according to an embodiment of the present invention will be described in more detail with reference to examples. However, the invention is not limited to the following examples.

Example 1

As an anode, a 15 Ω/cm ² (1200 angstrom) ITO glass substrate manufactured by Corning was cut to a size of 50 mm × 50 mm × 0.7 mm, and ultrasonically oscillated with isopropyl alcohol and pure water for 5 minutes, followed by irradiation with ultraviolet rays 30. Minutes, followed by exposure to ozone. The resulting ITO glass substrate was then placed in a vacuum deposition apparatus.

Compound 301, compound 35 and compound 502 were vacuum-deposited on an ITO glass substrate at a weight ratio of 60:40:1 to form a first charge-generating layer having a thickness of 100 angstroms, followed by compound 301 and compound 35 at a weight ratio of 60:40. Vacuum is co-deposited on the first charge generation layer to form a first mixed layer having a thickness of 400 angstroms. Next, the compound 301, the compound 35, and the compound 502 are vacuum-deposited on the first mixed layer at a weight ratio of 60:40:1 to form a second charge generating layer having a thickness of 100 angstroms, and the compound 301 and the compound 35 are then subjected to a weight ratio. A 60:40 vacuum was co-deposited on the second charge generating layer to form a second mixed layer having a thickness of 400 angstroms.

Compound 301 was vacuum deposited on the second mixed layer to form a buffer layer having a thickness of 230 angstroms.

ADN and DPVBi were co-deposited on the buffer layer at a weight ratio of 98:2 to form a light-emitting layer having a thickness of 300 angstroms.

Next, Alq _{3 was} vacuum deposited on the light-emitting layer to form an electron transport layer having a thickness of 300 Å.

Lithium fluoride, which is a halogen alkali metal, is vacuum deposited on an electron buffer layer after vacuum deposition of Al (cathode) having a thickness of 3000 angstroms to form an electron injecting layer having a thickness of 10 angstroms to form a LiF/Al electrode, thereby completing Manufacture of organic light-emitting diodes.

Example 2

The organic light-emitting diode was fabricated in the same manner as in Example 1, except that when the first charge generating layer and the second charge generating layer were formed, Compound 301, Compound 35, and Compound 502 in a weight ratio of 70:30:1 were used, and When the first mixed layer and the second mixed layer were formed, Compound 301 and Compound 35 in a weight ratio of 70:30 were used.

Example 3

The organic light-emitting diode was fabricated in the same manner as in Example 1, except that when the first charge generating layer and the second charge generating layer were formed, Compound 301, Compound 35, and Compound 502 in a weight ratio of 70:30:3 were used, and When the first mixed layer and the second mixed layer were formed, Compound 301 and Compound 35 in a weight ratio of 70:30 were used.

Example 4

The organic light-emitting diode was fabricated in the same manner as in Example 1, except that when the first charge generating layer and the second charge generating layer were formed, Compound 301, Compound 35, and Compound 502 in a weight ratio of 80:20:1 were used, and When the first mixed layer and the second mixed layer were formed, Compound 301 and Compound 35 in a weight ratio of 80:20 were used.

Comparative example 1

The organic light-emitting diode was fabricated in the same manner as in Example 2 except that no buffer layer was formed.

Comparative example 2

The organic light-emitting diode was fabricated in the same manner as in Example 1, except that instead of forming the first charge generating layer, the first mixed layer, the second charge generating layer, and the second mixed layer, 2-TNATA was vacuum deposited on the ITO glass substrate. To form a single hole injection layer having a thickness of 600 angstroms.

Evaluation example

According to the organic light-emitting diodes manufactured in Examples 1 to 4 and Comparative Examples 1 to 2 of the present invention, the driving voltage, the y value of the CIE chromaticity diagram, the luminous efficiency, and the lifetime are measured by using a PR650 (photometer) light source. The unit (manufactured by PhotoResearch Company) was measured, and the results are shown in Table 1 below.

Referring to Table 1, an organic light-emitting diode according to an embodiment of the present invention is compared to an organic light-emitting diode (Comparative Examples 1 to 2) including a hole transport layer having no buffer layer or no multilayer structure. (Examples 1 to 4) have a long life.

Fig. 3 is a graph showing the life characteristics of the organic light-emitting diodes prepared according to Examples 1 to 4 and the organic light-emitting diodes obtained according to Comparative Examples 1 and 2. Referring to FIG. 3, it is confirmed that an organic light-emitting diode (Comparative Examples 1 to 2) including a hole transport layer not having a buffer layer or having no multilayer structure, according to an embodiment of the present invention The organic light-emitting diodes (Examples 1 to 4) have a life expectancy of 3 to 12 times.

Referring to Table 1, it is confirmed that the organic light-emitting diode according to an embodiment of the present invention is compared to an organic light-emitting diode (Comparative Examples 1 to 2) including a hole transport layer having no multilayer structure. (Examples 1 to 4) have a preferred luminous efficiency of about 30%.

An organic light-emitting diode according to an embodiment of the present invention has improved charge balance, high efficiency, and long life characteristics due to a multilayer hole transport layer including a hole transport compound and a combination of charge generation materials having different energy levels. .

While the present invention has been shown and described with reference to the embodiments of the present invention, it will be understood by those of ordinary skill in the art .

100‧‧‧Organic Luminescent Diodes

120‧‧‧first electrode

130‧‧‧ hole injection layer

141‧‧‧First charge generation layer

142‧‧‧ first mixed layer

143‧‧‧Second charge generation layer

144‧‧‧Second mixed layer

140‧‧‧ hole transport layer

150‧‧‧buffer layer

160‧‧‧Lighting layer

170‧‧‧Electronic transport layer

180‧‧‧electron injection layer

190‧‧‧second electrode

Claims (20)

An organic light emitting diode comprising: a first electrode; a second electrode facing the first electrode; a light emitting layer interposed between the first electrode and the second electrode; a first mixed layer, Between the luminescent layer and the first electrode and comprising a first compound and a second compound; a second mixed layer interposed between the luminescent layer and the first mixed layer and comprising a third compound and a fourth compound; a first charge generating layer interposed between the first mixed layer and the first electrode and comprising the first compound, the second compound and a first charge generating material; and a second charge generating a layer between the first mixed layer and the second mixed layer and comprising the third compound, the fourth compound and a second charge generating material; and a buffer layer interposed between the light emitting layer and the second layer Between the mixed layers, wherein the first compound and the third compound are each independently a compound represented by the following Chemical Formula 1, and the second compound and the fourth compound are each independently a compound represented by the following Chemical Formula 2: <Chemical Formula 1> Wherein, in Chemical Formula 1, Ar ₁₁ and Ar ₁₂ are each independently a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group; and e and f are each independently an integer of 0 to 5; R ₅₁ To R ₅₈ and R ₆₁ to R ₆₉ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine group, a hydrazine group, a carboxyl group, and a salt thereof. , sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or Unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or Unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio; and R ₅₉ Is a phenyl group, a naphthyl group, an anthracenyl group, a biphenyl group or a pyridyl group, or at least one hydrogen atom with at least one atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, or a combination Ammonia, hydrazine, carboxyl and their salts, sulphur Root and its salts, and phosphate salts of a substituted or unsubstituted of C ₁ -C ₂₀ alkyl, unsubstituted of substituted or unsubstituted C ₁ -C ₂₀ alkoxy group of the phenyl group, Naphthyl, anthracenyl, biphenyl or pyridyl; Wherein, in Chemical Formula 2, Ar ₁ to Ar ₃ are each independently a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group; and a and b are each independently an integer of 0 to 5; An integer from 1 to 5; R ₁ to R ₅ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, a hydrazine, a hydrazine, a carboxyl group, and Salts, sulfonates and their salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl groups, substituted or unsubstituted C ₂ -C ₆₀ alkenyl groups, Substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, via Substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio, Si(R ₃₁ )(R ₃₂ )(R ₃₃ ), —N(R ₃₄ )(R ₃₅ ) or a nitrogen atom-containing group, and at least one of R ₁ to R ₅ is a nitrogen atom-containing group; d is 0 An integer of up to 5; R ₁₁ to R ₂₃ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, or a cyanogen Base, nitro, amine, formamidine, hydrazine, hydrazine, carboxyl and its salts, sulfonate and its salts, phosphate and its salts, substituted or unsubstituted C ₁ -C ₆₀ Alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy a substituted, unsubstituted C ₃ -C ₆₀ cycloalkyl group, a substituted or unsubstituted C ₅ -C ₆₀ aryl group, a substituted or unsubstituted C ₅ -C ₆₀ aryloxy group a substituted, unsubstituted C ₅ -C ₆₀ arylthio group, -Si(R ₃₆ )(R ₃₇ )(R ₃₈ ) or -N(R ₃₉ )(R ₄₀ ); and R ₃₁ to R _{The 40} series are independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a methyl group, a hydrazine, a hydrazine, a carboxyl group, a salt thereof, a sulfonate group and a salt thereof, Phosphate and its salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C _3- C ₆₀ cycloalkyl, substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C _5- C ₆₀ arylthio group or substituted or unsubstituted C ₂ -C ₆₀ heteroaryl group; wherein the nitrogen atom-containing group is a 5-membered aromatic ring group containing a nitrogen atom as a ring atom, A 6-membered aromatic ring group having a nitrogen atom as a ring atom or a 9-membered aromatic ring group formed by a nitrogen atom as a ring atom and fused by a 5-membered aryl group and a 6-membered aryl group. The organic light-emitting diode according to claim 1, wherein the highest compounding sub-track domain (HOMO) energy level of the second compound is lower than the highest filling sub-orbital energy level of the first compound by 0.1 eV. Up to 0.2 eV, and the lowest unfilled sub-orbital domain (LUMO) energy level of the second compound is lower than the lowest unfilled sub-orbital energy level of the first compound by 0.1 eV to 0.2 eV. The organic light-emitting diode according to claim 1, wherein the first compound has a hole mobility higher than a hole mobility of the second compound. The organic light-emitting diode according to claim 1, wherein the first compound and the third compound are each independently represented by the following chemical formula 1A: In the chemical formula 1A, R ₅₁ , R ₅₉ , R ₆₁ and R ₆₂ are the same as those in the chemical formula 1. The organic light-emitting diode according to claim 1, wherein the first compound and the third compound are each independently the following compound 301: The organic light-emitting diode according to claim 1, wherein the second compound and the fourth compound are each independently at least one of the compounds represented by the following chemical formulas 2A to 2K: <Chemical Formula 2C><Chemical Formula 2D> <Chemical Formula 2I><Chemical Formula 2J> Wherein, in Chemical Formulas 2A to 2K, Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted C ₅ -C ₆₀ exoaryl group; and a and b are each independently an integer of 0 to 5; R _1a , R _1b and R ₃ are each independently a nitrogen-containing atom; R ₁₁ , R ₁₉ and R ₂₀ are each independently substituted or unsubstituted C ₁ -C ₆₀ alkyl and substituted or Unsubstituted C ₅ -C ₆₀ aromatic group; Z ₁ to Z ₄ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group, an amine group, a formazan group, and a combination. Ammonia, hydrazine, carboxyl and their salts, sulfonate and its salts, phosphates and their salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, substituted or unsubstituted C ₂ - C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted or unsubstituted C ₅ -C ₆₀ arylthio, -Si(Q ₁ )(Q ₂ )(Q ₃ ) or -N(Q ₄ )(Q ₅ ), And if x or y is 2 or more, the plurality of Z ₁ or Z ₂ are the same or different from each other; and Q ₁ to Q ₅ are each independently a hydrogen atom, a halogen atom, a halogen atom, a hydroxyl group, a cyano group, a nitro group. , amine, carbaryl, hydrazine, hydrazine, carboxyl and salts thereof, sulfonate and its salts, phosphate and its salts, substituted or unsubstituted C ₁ -C ₆₀ alkyl, Substituted or unsubstituted C ₂ -C ₆₀ alkenyl, substituted or unsubstituted C ₂ -C ₆₀ alkynyl, substituted or unsubstituted C ₁ -C ₆₀ alkoxy, substituted Or unsubstituted C ₃ -C ₆₀ cycloalkyl, substituted or unsubstituted C ₅ -C ₆₀ aryl, substituted or unsubstituted C ₅ -C ₆₀ aryloxy, substituted Or an unsubstituted C ₅ -C ₆₀ arylthio group or a substituted or unsubstituted C ₂ -C ₆₀ heteroaryl group; x is an integer from 1 to 8; and y is an integer from 1 to 3. The organic light-emitting diode according to claim 1, wherein the second compound and the fourth compound are independently the following compounds 2, 8, 14, 15, 16, 20, 31 and 35, respectively. At least one: The organic light-emitting diode according to claim 1, wherein the first charge generating material and the second charge generating material are each independently at least one of the following compounds 501 and 502: <Compound 501><Compound502> The organic light-emitting diode according to claim 1, wherein the mixing ratio of the first compound to the second compound is in the range of 6:4 to 8:2. The organic light-emitting diode according to claim 1, wherein the mixing ratio of the third compound to the fourth compound is in the range of 6:4 to 8:2. The organic light-emitting diode according to claim 1, wherein each of the first mixed layer and the second mixed layer has a thickness ranging from 40 nm to 60 nm. The organic light-emitting diode according to claim 1, wherein the first charge generating material is in an amount of from 1 to 3 parts by weight based on 100 parts by weight of the first charge generating layer. The organic light-emitting diode according to claim 1, wherein the second charge generating material is in an amount of from 1 to 3 parts by weight based on 100 parts by weight of the second charge generating layer. The organic light-emitting diode according to claim 1, wherein each of the first charge generating layer and the second charge generating layer has a thickness ranging from 10 nm to 20 nm. The organic light-emitting diode according to claim 1, wherein the buffer layer The compound represented by Chemical Formula 1 is contained. The organic light-emitting diode according to claim 1, wherein the buffer layer has a thickness ranging from 0.1 nm to 30 nm. The organic light emitting diode according to claim 1, wherein the first mixed layer contacts the first charge generating layer. The organic light emitting diode according to claim 1, wherein the second mixed layer contacts the second charge generating layer. The organic light emitting diode according to claim 1, wherein the organic light emitting diode comprises a hole blocking layer, an electron transport layer, an electron injecting layer, and one of an electron transport function and an electron injecting function. At least one layer of the functional layer, and the at least one layer is interposed between the light emitting layer and the second electrode. A planar display device comprising: a transistor including a source, a drain, a gate, and an active layer; and the organic light emitting diode according to claim 1, wherein the organic light emitting diode The first electrode of the pole body is electrically connected to the source or the drain.